Replace shutdown_room and purge_room APIs with delete_room

[anoadragon453]

Synapse is dropping the shutdown_room and purge_room APIs in favour of the delete_room API which handles both operations and more. Context: matrix-org/synapse#8829

Please update your code to use this new endpoint instead :slight_smile:

[richvdh]

Hi mjolnir maintainers (@turt2live?), quick reminder that we're planning to drop support for these APIs in Synapse in a couple of weeks.

[turt2live]

@richvdh There's theoretically a team which manages Mjolnir these days. I'll bring it up with them.

[richvdh]

Hi folks, just a reminder that we'll be disabling these APIs on develop as soon as we've cut Synapse 1.41rc1, which is due to happen today - so it's likely that matrix.org will drop the old APIs within the next couple of days.